Bamboo sharks develop independently of their mother inside leathery egg cases for five months. During this time they are extremely vulnerable to predators and have to remain undetected in order to survive.

It's know that predators, such as sharks, have highly sensitive electroreceptors that they use to detect electrical fields emitted by their prey. Previously no one has studied whether this mechanism can be used by prey animals to avoid their predators.

Ryan Kempster from the University of Western Australia and colleagues collected and monitored 11 bamboo shark embryo from the Underwater World and Daydream Island Resort aquaria in Queensland, Australia.

The embryos were placed in an aquarium and the water was stimulated to mimic the electrical field given off by a predator at various stages of their development. In the later stages, the sharks were able to detect the electrical field and quickly froze, even stopping their gill movements to decrease their own electrical field and avoid detection

The research is important for developing a shark repellent to keep humans from being attacked. This would involve sending out electrical signals that sharks are afraid of. On the flip side, the electrical field can also be used to protect the millions of sharks that accidentally get caught on fishing hooks each year.